冻融循环下钢渣粉水泥改良膨胀土室内试验研究  

EXPERIMENTAL STUDY ON PHYSICAL AND MECHANICAL PROPERTIES OF EXPANSIVE SOIL IMPROVED BY STEEL SLAG POWDER CEMENT UNDER FREEZE-THAW CYCLE

作　　者：吴燕开[1,2] 苗盛瑶 李鑫 王浩 曹玉鹏 胡兴涛 WU Yankai;MIAO Shengyao;LI Xin;WANG Hao;CAO Yupeng;HU Xingtao(Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation,Qingdao 266590,China;Shandong University of Science and Technology,School of Civil Engineering and Architecture,Qingdao 266590,China;Shandong University of Science and Technology,School of Transportation,Qingdao 266590,China;Taian Boao Safety Evaluation Co.,Ltd.,Taian 271000,China)

机构地区：[1]山东科技大学,山东省土木工程防灾减灾重点实验室,中国青岛266590 [2]山东科技大学土木工程与建筑学院,中国青岛266590 [3]山东科技大学交通学院,中国青岛266590 [4]泰安博奥安全评价有限公司,中国泰安271000

出　　处：《工程地质学报》2021年第3期851-861,共11页Journal of Engineering Geology

基　　金：国家自然科学青年基金项目(资助号:51608312);山东科技大学科研创新团队支持项目(资助号:2015KYDT104).

摘　　要：膨胀土遇水膨胀失水收缩,是一种不良的工程地质土体。本文采用水泥、钢渣粉和NaOH改良膨胀土,对其经受不同冻融循环作用次数的冻融循环试验,并将冻融试验后的改良膨胀土及未改良膨胀土进行体积、自由膨胀率、无侧限抗压强度等物理力学性质测试,同时进行微观电镜扫描分析,研究冻融循环作用下钢渣粉水泥改良膨胀土的物理力学特性变化规律。试验结果表明,在冻融循环作用下,改良后的膨胀土与未改良膨胀土相比,体积变化率明显降低。随养护龄期的增长,改良后的膨胀土在冻融循环作用下体积膨胀变小,随冻融循环次数的增加,体积变化率趋于平稳,自由膨胀率降低。冻融循环作用下,钢渣粉水泥改良膨胀土(ES-SSP-C)试样的无荷膨胀率较低,改良后的膨胀土较未改良膨胀土具有较好的抗膨胀性能,掺NaOH活性激发剂的钢渣粉水泥改良膨胀土(ES-SSP-C-SH)抗膨胀性能效果最为明显。Expansive soil is a kind of poor engineering geology soil because it has the property of water expansion and water shrinkage.In this paper,cement,steel slag powder and NaOH are used to improve the expansive soil and carry out the freeze-thaw cycle test.Then,the physical and mechanical properties of the improved expansive soil and the unmodified expansive soil after different freeze-thaw cycles are tested,such as volume,free expansion rate and unconfined compressive strength.At the same time,the micro electron microscope scanning analysis is carried out,in order to study the change rule of physical and mechanical properties of expansive soil improved by steel slag cement under the action of freeze-thaw cycle.The test results show that:Under the action of freeze-thaw cycle,the volume change rate of improved expansive soil is significantly lower than that of unmodified expansive soil.With the increase of curing age,the volume expansion of the improved expansive soil becomes smaller under the action of freeze-thaw cycles.With the increase of freeze-thaw cycles,the volume change rate tends to be stable,and the free expansion rate decreases with the increase of freeze-thaw cycles.Under the action of freeze-thaw cycle,the no-load expansion rate of ES-SSP-C sample is low.Under the action of freeze-thaw cycle,the improved expansive soil has better anti expansion performance than the unmodified expansive soil,and the effect of steel slag powder cement modified expansive soil(ES-SSP-C-SH)with NaOH active activator is the most obvious.

关 键 词：冻融循环 膨胀土 体积变化率 自由膨胀率 无荷膨胀率 无侧限抗压强度 

分 类 号：TU443[建筑科学—岩土工程]